Validating Synthetic Galaxy Catalogs for Dark Energy Science in the LSST Era

TL;DR

This paper introduces a comprehensive validation framework for synthetic galaxy catalogs, ensuring they realistically replicate observed galaxy properties for dark energy research in the LSST era.

Contribution

It presents a suite of validation tests tailored for cosmology surveys, specifically designed to assess the realism of simulated galaxy catalogs like cosmoDC2.

Findings

Validation tests effectively identify discrepancies in galaxy properties

The framework is adaptable to different scientific goals

cosmoDC2 passes key validation criteria for LSST DESC use

Abstract

Large simulation efforts are required to provide synthetic galaxy catalogs for ongoing and upcoming cosmology surveys. These extragalactic catalogs are being used for many diverse purposes covering a wide range of scientific topics. In order to be useful, they must offer realistically complex information about the galaxies they contain. Hence, it is critical to implement a rigorous validation procedure that ensures that the simulated galaxy properties faithfully capture observations and delivers an assessment of the level of realism attained by the catalog. We present here a suite of validation tests that have been developed by the Rubin Observatory Legacy Survey of Space and Time (LSST) Dark Energy Science Collaboration (DESC). We discuss how the inclusion of each test is driven by the scientific targets for static ground-based dark energy science and by the availability of suitable validation data. The validation criteria that are used to assess the performance of a catalog are flexible and depend on the science goals. We illustrate the utility of this suite by showing examples for the validation of cosmoDC2, the extragalactic catalog recently released for the LSST DESC second Data Challenge.